Heretofore, it has been known to form a multilayered flap in a corner of a body of sheet material, and to fold this flap back upon the body of the sheet material. Usually, the flap is mechanically pressed against the body of sheets as it is folded thereupon. Patents showing this method are numerous:
F. L. Gregory, U.S. Pat. No. 689,394, issued Dec. 24, 1901;
E. L. Miller, U.S. Pat. No. 1,302,920, issued June 17, 1919;
A. Nassano, U.S. Pat. No. 1,387,164, issued Aug. 9, 1921;
H. A. W. Wood, U.S. Pat. No. 2,107,462, issued Feb. 8, 1938;
H. J. Jewell, U.S. Pat. No. 2,749,816, issued June 12, 1956;
J. P. Thor, U.S. Pat. No. 2,874,666, issued Feb. 24, 1959; and
R. A. Sherman, U.S. Pat. No. 3,233,526, issued Feb. 8, 1966.
While the above methods of fastening the sheets of paper together are generally adequate, they do not provide as strong a bond as when using a mechanical fastener such as a clip, staple, or pin, etc.
This invention was conceived as a way to provide a superior mechanical paper bond in a plurality of sheets, which will more nearly approach the bond strength of a mechanical fastening of the paper, than prior paper bonded methods.